1. Field of the Invention
The present invention relates to an organic light emitting display device, and more particularly, to encapsulating the organic light emitting display device.
2. Description of Related Art
Generally, an organic light emitting display (OLED) includes an anode electrode layer, a hole transport layer, an organic emission layer, and an electron transport layer, which are sequentially formed on the anode electrode layer, and a cathode electrode layer formed on the resultant structure. In such a structure, when a voltage is applied, a hole injected from the anode electrode layer moves to the organic emission layer via the hole transport layer, and an electron injected from the cathode electrode layer moves to the organic emission layer via the electron transport layer, so that carriers of the hole and electron combine in the organic emission layer to create excitons. The organic emission layer emits light by energy generated when the excitons created as described above make the transition from an excited state to a ground state.
However, organic thin layers formed of an organic compound having low thermal resistivity is likely to be degraded by moisture, and a cathode electrode formed on the organic thin layers can be lowered in performance due to oxidation. Therefore, the organic thin layers should be hermetically sealed to prevent moisture or oxygen from contacting the thin layers. FIG. 1 is a cross-sectional view of an exemplary organic light emitting display. As shown in FIG. 1, an organic light emitting diode 110 is formed on a substrate 100. The substrate 100 includes a thin film transistor having a semiconductor layer, a gate electrode, a source electrode, and a drain electrode. Then, after forming a moisture absorption layer 130 on one surface of a sealing substrate 140 facing the organic light emitting diode 110, the substrate 100 and the sealing substrate 140 are adhered to each other using a sealant 120, thereby completing an organic light emitting display.